Radial flow oil shale retort

ABSTRACT

A radial flow oil shale retort can include a central heating fluid conduit having a permeable outer wall and an outer heating fluid annulus positioned about the central heating fluid conduit, the outer heating fluid annulus having a permeable inner wall. An annular body of comminuted oil shale can be between the permeable outer wall of the central heating fluid conduit and the permeable inner wall of the outer heating fluid annulus. A heating fluid supply can be connected to either the central heating fluid conduit or the outer heating fluid annulus to flow a heating fluid in a radial direction through the annular body of the comminuted oil shale.

RELATED APPLICATION

This application claims priority to U.S. Provisional Application No.62/857,016, filed Jun. 4, 2019 which is incorporated herein byreference.

BACKGROUND

Many processes have been developed for producing hydrocarbons fromvarious hydrocarbonaceous materials such as oil shale and tar sands.Generally, methods for recovering hydrocarbon products from oil shalehave involved applying heat to the oil shale. Heating oil shale allowskerogen in the oil shale to break down through the process of pyrolysis,yielding liquid and vapor hydrocarbon compounds. Although someprocessing techniques and equipment have improved performance, operatingcosts, maintenance, and processing continue to present challenges whichare difficult to overcome.

SUMMARY

A radial flow oil shale retort can include a central heating fluidconduit having a permeable outer wall. An outer heating fluid annuluscan be positioned about the central heating fluid conduit, the outerheating fluid annulus having a permeable inner wall. An annular body ofcomminuted oil shale can be between the permeable outer wall of thecentral heating fluid conduit and the permeable inner wall of the outerheating fluid annulus. A heating fluid supply can be connected to eitherthe central heating fluid conduit or the outer heating fluid annulus toflow a heating fluid in a radial direction through the annular body ofcomminuted oil shale.

In one example, the heating fluid supply is connected to the centralheating fluid conduit to flow the heating fluid in a direction from thecentral heating fluid conduit to the outer heating fluid annulus. In yetanother example, the heating fluid supply is connected to the outerheating fluid annulus to flow the heating fluid in a direction from theouter heating fluid annulus to the central heating fluid conduit. Infurther examples, the retort can include a catalytic heater in thecentral heating fluid conduit or in the outer heating fluid annulus,wherein the catalytic heater produces heat by a chemical reaction ofhydrocarbons in the heating fluid.

The retort can also include a rotary shale distributor positioned abovethe annular body of comminuted oil shale to distribute oil shale betweenthe permeable outer wall of the central heating fluid conduit and thepermeable inner wall of the outer heating fluid annulus.

In a particular example, the heating fluid comprises steam and in mostcases is predominately steam. In another example, the heating fluidcomprises hydrocarbons and in most cases is predominately hydrocarbons.In yet another example, the heating fluid comprises oxygen and/ormixtures of gases containing at least some percentage of oxygen.

The retort can also include a combustor unit and a shale withdrawalconduit to convey spent shale to the combustor, wherein the combustorgenerates heat by combusting the spent shale. In certain examples, thecombustor is a fluid bed combustor or a down flow bed combustor. Inother examples, the retort can include a vapor/gas product outletconnected to either the central heating fluid conduit or the outerheating fluid annulus, whichever is not connected to the heating fluidsupply. In still other examples, the retort can include a liquid productoutlet in fluid communication with the annular body of comminuted oilshale to collect liquid hydrocarbon products produced from thecomminuted oil shale.

In yet other examples, the retort can include a heating unit connectedto the heating fluid supply to heat the heating fluid before the heatingfluid flows through the annular body of comminuted oil shale. In furtherexamples, the dimensions of the retort can include the diameter at theouter walls of the retort from 10 feet to 100 feet or about 40 feet; thediameter at the permeable inner wall of the outer heating fluid annulusfrom 9 feet to 90 feet or about 38 feet; the diameter at the permeableouter walls of the central heating fluid conduit from 1 foot to 10 feetor about 6 feet; a bed depth measured from the permeable outer wall ofthe central heating fluid conduit to the permeable inner wall of theouter heating fluid annulus from 1 foot to 80 feet or about 16 feet; abed height measured in the axial direction of the retort from 10 feet to300 feet.

A complimentary method of extracting hydrocarbons from oil shale caninclude loading comminuted oil shale into a radial flow oil shaleretort, wherein the radial flow oil shale retort comprises: a centralheating fluid conduit having a permeable outer wall, and an outerheating fluid annulus positioned about the central heating fluidconduit, the outer heating fluid annulus having a permeable inner wall,wherein the comminuted oil shale is loaded into a space between thepermeable outer wall of the central heating fluid conduit and thepermeable inner wall of the outer heating fluid annulus. A heating fluidcan flow in a radial direction between the central heating fluid conduitand the outer heating fluid annulus to heat the comminuted oil shale andextract hydrocarbons therefrom, and the hydrocarbons can be collected.

In some examples, the comminuted oil shale is substantially stationaryduring the extraction of the hydrocarbons, and further comprisingloading and unloading the comminuted oil shale from the retort, suchthat the process is a batch process. In other examples, the comminutedoil shale continuously flows through the retort such that the process iscontinuous. In certain examples, the method can include continuouslyloading comminuted oil shale into the retort and continuouslywithdrawing spent oil shale from the retort. Where the shale is flowingin an annulus, the rate of flow can be a function of the dimensions, andthe rate of heating the shale to retort temperature. Flow rate is also afunction of the recirculation of the heating medium and composition ofthe heating medium that transfer heat to the cold shale. In a particularexample, the comminuted oil shale can flow downward at a speed of 1 inchper hour to 10 feet per hour.

There has thus been outlined, rather broadly, the more importantfeatures of the invention so that the detailed description thereof thatfollows may be better understood, and so that the present contributionto the art may be better appreciated. Other features of the presentinvention will become clearer from the following detailed description ofthe invention, taken with the accompanying drawings and claims, or maybe learned by the practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section illustration of a radial flow oil shale retortin accordance with an embodiment of the present invention;

FIG. 2 is a process flow diagram for processing oil shale using a radialflow oil shale retort in accordance with an embodiment of the presentinvention;

FIG. 3 is a cross-section illustration of a radial flow oil shale retorthaving optional catalytic converters in accordance with an embodiment ofthe present invention;

FIG. 4 is a process flow diagram for processing oil shale using a radialflow oil shale retort in accordance with another embodiment of thepresent invention;

FIG. 5 is a cross-section illustration of a radial flow oil shale retorthaving a distribution screen within the outer heating fluid annulus andwith flexible temperature zone control in accordance with another aspectof the present invention; and

FIG. 6 is a flowchart illustrating a method of processing a body ofheated material using radial heat flow in accordance with an embodimentof the present invention.

These drawings are provided to illustrate various aspects of theinvention and are not intended to be limiting of the scope in terms ofdimensions, materials, configurations, arrangements or proportionsunless otherwise limited by the claims.

DETAILED DESCRIPTION

While these exemplary embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, it should beunderstood that other embodiments may be realized and that variouschanges to the invention may be made without departing from the spiritand scope of the present invention. Thus, the following more detaileddescription of the embodiments of the present invention is not intendedto limit the scope of the invention, as claimed, but is presented forpurposes of illustration only and not limitation to describe thefeatures and characteristics of the present invention, to set forth thebest mode of operation of the invention, and to sufficiently enable oneskilled in the art to practice the invention. Accordingly, the scope ofthe present invention is to be defined solely by the appended claims.

Definitions

In describing and claiming the present invention, the followingterminology will be used.

As used herein, “hydrocarbonaceous material” refers to anyhydrocarbon-containing material from which hydrocarbon products can beextracted or derived. For example, hydrocarbons may be extracteddirectly as a liquid, removed via solvent extraction, directlyvaporized, by conversion from a feedstock material, or otherwise removedfrom the material. Many hydrocarbonaceous materials contain kerogen orbitumen which is converted to a flowable or recoverable hydrocarbonthrough heating and pyrolysis. Hydrocarbonaceous materials can include,but are not limited to, oil shale, tar sands, coal, lignite, bitumen,peat, and other organic rich rock. Thus, existing hydrocarbon-containingmaterials can be upgraded and/or released from such feedstock through achemical conversion into more useful hydrocarbon products. Chemicalconversion can include synthesis reactions, decomposition reactions orother reactions which result in chemically distinct product compounds.Such chemical conversions can be accomplished thermally, catalytically,and/or via addition of other chemical components.

As used herein, “spent hydrocarbonaceous material” and “spent oil shale”refer to materials that have already been used to produce hydrocarbons.Typically after producing hydrocarbons from a hydrocarbonaceousmaterial, the remaining material is mostly mineral with the organiccontent largely removed. In some cases, spent oil shale can have asufficient amount of residual hydrocarbon or carbon content that thespent oil shale can be burned in a combustor to generate additionalheat.

As used herein, “lean hydrocarbonaceous material” and “lean oil shale”refer to materials that have a relatively low hydrocarbon content. As anexample, lean oil shale can typically have from 1% to 8% hydrocarboncontent by weight.

As used herein, “rich hydrocarbonaceous material” and “rich oil shale”refer to materials that have a relatively high hydrocarbon content. Asan example, rich oil shale can typically have from 12% to 27%hydrocarbon content by weight, and some cases higher.

Many examples described herein involve processing of oil shale. In somecases, these examples can also be made and used with other types ofhydrocarbonaceous material other than oil shale.

As used herein, whenever any property is referred to that can have adistribution between differing values, such as a temperaturedistribution, particle size distribution, etc., the property beingreferred to represents an average of the distribution unless otherwisespecified. Therefore, “particle size of the comminuted oil shale” refersto an average particle size, and “temperature of the body of comminutedoil shale” refers to an average temperature of the body of comminutedoil shale.

It is noted that, as used in this specification and in the appendedclaims, the singular forms “a,” “an,” and “the” include plural referentsunless the context clearly dictates otherwise. Thus, for example,reference to “a layer” includes one or more of such features, referenceto “a particle” includes reference to one or more of such elements, andreference to “producing” includes reference to one or more of suchsteps.

As used herein, the terms “about” and “approximately” are used toprovide flexibility, such as to indicate, for example, that a givenvalue in a numerical range endpoint may be “a little above” or “a littlebelow” the endpoint. The degree of flexibility for a particular variablecan be readily determined by one skilled in the art based on thecontext. However, unless otherwise enunciated, the term “about”generally connotes flexibility of less than 2%, and most often less than1%, and in some cases less than 0.01%.

As used herein, the term “substantially” refers to the complete ornearly complete extent or degree of an action, characteristic, property,state, structure, item, or result. The exact allowable degree ofdeviation from absolute completeness may in some cases depend on thespecific context. However, the nearness of completion will generally beso as to have the same overall result as if absolute and totalcompletion were obtained. “Substantially” refers to a degree ofdeviation that is sufficiently small so as to not measurably detractfrom the identified property or circumstance. The exact degree ofdeviation allowable may in some cases depend on the specific context.The use of “substantially” is equally applicable when used in a negativeconnotation to refer to the complete or near complete lack of an action,characteristic, property, state, structure, item, or result.

As used herein, “adjacent” refers to the proximity of two structures orelements. Particularly, elements that are identified as being “adjacent”may be either abutting or connected. Such elements may also be near orclose to each other without necessarily contacting each other. The exactdegree of proximity may in some cases depend on the specific context.Additionally, adjacent structures or elements can in some cases beseparated by additional structures or elements between the adjacentstructures or elements.

As used herein, a plurality of items, structural elements, compositionalelements, and/or materials may be presented in a common list forconvenience. However, these lists should be construed as though eachmember of the list is individually identified as a separate and uniquemember. Thus, no individual member of such list should be construed as ade facto equivalent of any other member of the same list solely based ontheir presentation in a common group without indications to thecontrary.

Concentrations, amounts, and other numerical data may be presentedherein in a range format. It is to be understood that such range formatis used merely for convenience and brevity and should be interpretedflexibly to include not only the numerical values explicitly recited asthe limits of the range, but also to include all the individualnumerical values or sub-ranges encompassed within that range as if eachnumerical value and sub-range is explicitly recited. For example, anumerical range of about 1 to about 4.5 should be interpreted to includenot only the explicitly recited limits of 1 to about 4.5, but also toinclude individual numerals such as 2, 3, 4, and sub-ranges such as 1 to3, 2 to 4, etc. The same principle applies to ranges reciting only onenumerical value, such as “less than about 4.5,” which should beinterpreted to include all of the above-recited values and ranges.Further, such an interpretation should apply regardless of the breadthof the range or the characteristic being described.

Any steps recited in any method or process claims may be executed in anyorder and are not limited to the order presented in the claims.Means-plus-function or step-plus-function limitations will only beemployed where for a specific claim limitation all of the followingconditions are present in that limitation: a) “means for” or “step for”is expressly recited; and b) a corresponding function is expresslyrecited. The structure, material or acts that support the means-plusfunction are expressly recited in the description herein. Accordingly,the scope of the invention should be determined solely by the appendedclaims and their legal equivalents, rather than by the descriptions andexamples given herein.

Reference will now be made to the exemplary embodiments illustrated, andspecific language will be used herein to describe the same. It willnevertheless be understood that no limitation of the scope of thetechnology is thereby intended. Additional features and advantages ofthe technology will be apparent from the detailed description whichfollows, taken in conjunction with the accompanying drawings, whichtogether illustrate, by way of example, features of the technology.

With the general examples set forth in the Summary above, it is noted inthe present disclosure that when describing the system, or the relateddevices or methods, individual or separate descriptions are consideredapplicable to one other, whether or not explicitly discussed in thecontext of a particular example or embodiment. For example, indiscussing a device per se, other device, system, and/or methodembodiments are also included in such discussions, and vice versa.

Furthermore, various modifications and combinations can be derived fromthe present disclosure and illustrations, and as such, the followingfigures should not be considered limiting.

Radial Flow Oil Shale Retorts

In various examples, radial flow oil shale retorts can have anycombination of the following features. In some examples, the retort canoperate as a batch process or a continuous process. As a batch process,the retort can be filled with comminuted oil shale, then the oil shalecan be heated for a period of time to extract hydrocarbons therefrom,and then the spent oil shale can be removed from the retort either aftera cooling step or while the spent shale is cooling. As a continuousprocess, the oil shale can be a moving bed. Fresh oil shale can becontinuously or periodically introduced at the top of the retort andspent oil shale can be withdrawn from the bottom of the retort. Suitablefilling and withdrawing equipment can be used, such as lock hoppers, oilshale distributors, feed pipes, withdrawal tubes, and so on.

As a general guideline, the heating fluid as a working fluid can flow ina radially inward direction or in a radially outward direction throughthe bed of oil shale. With inward flow, the heating fluid can beintroduced into an outer heating fluid annulus around the bed of oilshale. The heating fluid can then flow in an inward direction throughthe bed of oil shale and into a central heating fluid conduit. Withoutward flow, the heating fluid can flow in the opposite direction.

The oil shale can be contained in an annular space with permeable wallsto allow heating fluid to flow through particulate or crushed oil shale.The outer heating fluid annulus can include a permeable inner wall. Theinner heating fluid conduit can also include a permeable outer wall. Insome examples, the permeable walls can be rigid walls with holesperforating the walls, mesh baskets, layers of mesh or screen material,profile wire screen, or any other type of permeable wall that can allowheating fluid to pass through while maintaining the comminuted oil shalein the bed.

During processing, the retort can be heated by a heating fluid that isheated by an external heat source and supplied to the retort at thedesired heating temperature. The heating fluid can include hydrocarbongases, hydrocarbon vapors, steam, hot air, oxygen, and other fluids inany mixture or ratio. In one optional example, oxygen content in theheating fluid can be less than about 21%. In some cases, the workingfluid can be provided by a dedicated burner. Optionally, or in addition,the working fluid can be gaseous and vapor products recovered fromanother adjacent retort. For example, non-condensed hydrocarbon productmixed with a heating fluid can be introduced into the retort as aworking fluid.

In other examples, the retort can include a catalytic heater that cangenerate heat by reaction of hydrocarbons with oxygen. In certainexamples, the heating fluid can include hydrocarbons and oxygen and theheating fluid can flow past or through a catalytic heater in the retort(or outside the retort before the heating fluid enters the retort) togenerate heat to heat the heating fluid. Combinations of these heatingmethods can be used, such as catalytic heating with supplemental steamheating, preheating hydrocarbon gases before further heating the gasesusing a catalytic heater, and so on. In some examples, the temperatureof the heating fluid can be from 800° F. to 1000° F. Non-limitingexamples of catalytic converter materials can include zeolites,heterogeneous catalysts, and the like. With these somewhat generalprinciples in mind, the following specific examples, illustrate variousmore detailed implementations which can be utilized.

FIG. 1 shows one example radial flow oil shale retort 100. Thisconfiguration can be operated as a moving bed retort where rubbilizedoil shale is fed through an inlet assembly 102 including an initial setof two six vane hopper valves 104. These hopper valves can selectivelycontrol the rate of oil shale flow into the retort body 106 throughadjustment of the rate of rotation of the vanes. An optionalintermediate purge line 108 can be used to introduce a carrier gas ifoil shale should become lodged in the inlet assembly 102. A rotatingshale distributor 110 can distribute the oil shale among multiple shalefeed pipes 112 which direct oil shale to the retort body 106. In oneexample, the feed pipes can be 20″ diameter shale feed pipes.

Within the retort body 106, the oil shale can be directed into anannular body of comminuted oil shale 114 between an outer heating fluidannulus 116 and a central fluid conduit 118. In this particular example,the outer heating fluid annulus 116 and central fluid conduit 118 can beconstructed as profile wire screens, e.g. as a Johnson screen, althoughany perforated barrier may be used which prevents comminuted oil shalefrom passing through while also allowing gases and liquids to pass. Thebottom of the retort 120 can be lined with abrasion resistant refractorymaterial.

Heating fluid (working gas) 122 can be introduced into the retort bodyat a heating fluid inlet 124. In one specific example, the working gascan be supplied at 800° F. to 1000° F. and flows in through a 36 inch to55 inch heating fluid inlet 124 in the retort body 106. The heatingfluid flows into an upper header portion 126 and then into the outerheating fluid annulus 116 oriented between the retort vessel wall 128and the permeable inner wall 130. The heating fluid then passes inwardlythrough the annular bed 114 of oil shale and through a permeable outerwall 132, and into the central heating fluid conduit 118. The heatingfluid flows from the central heating fluid conduit 118 to a fluid outlet134 at the bottom of the retort. In one example, the fluid outlet can bea 60 inch to 72 inch outlet.

As the heating fluid flows through the annular shale bed 114,hydrocarbons are removed from the oil shale or other carbonaceousmaterial and carried with the predominate quantity of heating fluid.This means that at the exit, the heating fluid is mixed with gaseous andvapor hydrocarbon products extracted from the oil shale. Spent oil shaleis withdrawn from the bottom of the retort through one or more spentshale outlets 136. In one example, spent shale outlets can include apair of six vane lock hopper valves 138 with an optional intermediatepurge 140. In one specific example, the spent shale outlets may be 20inch shale withdrawal tubes leading to a pair of six vane hopper valves.

Spent shale can be sent to a shale combustor to combust residualcarbonaceous material to generate heat which can be used in otherportions of the process (e.g. in a preheating cycle of an adjacentretort). Although dimensions can vary considerably based on designcriteria and desired throughput, in one specific example, the retortvessel inner diameter can be 40 feet, the basket permeable inner walldiameter can be 38 feet, the permeable outer walls diameter can be 6feet, the bed depth (horizontal distance between the basket and centerpipe walls) can be 16 feet, while the bed height can be from 40 feet to300 feet. The capacity of such a dimensioned retort can be about 276tons of oil shale per hour and the corresponding yield can be about 3400barrels per day of produced hydrocarbon product. Of course otherspecific dimensions can be designed for specific production parametersand these specific dimensions are provided merely as one example.

FIG. 2 shows additional description of the example of FIG. 1 where theradial flow oil shale retort 100 is integrated into a larger hydrocarbonrecovery system 200. The oil shale bed can be dry (as in, no liquidhydrocarbons are present) or the oil shale bed can include some liquidhydrocarbons produced from the oil shale. The liquid hydrocarbonproducts can be a mist that flows out with the heating fluid, or aliquid that drains to the bottom of the oil shale bed. The liquiddraining to the bottom of the oil shale can be collected at a drain atthe bottom of the retort 100. The working gas flow rate can be limitedto a rate that would bias or push the oil shale particles within theannular body 114 against the center pipe 132. A profile wire screen orother perforated wall structure is used to construct the permeable innerwall 130 of the outer heating fluid annulus 116 and center pipe 132 soas to withstand abrasive scraping and rubbing of the oil shale movingdownward. Although operating parameters can vary, the shale can mostoften move at a rate of 4 to 6 feet per hour downward. The retort vessel106 can be a hot wall or cold wall vessel. The bed depth can typicallybe less than in non-radial downflow retorts. Hot working gas or steamcan be used in or around the shale withdrawal tubes.

Spent shale from radial flow retort 100 can be sent to a combustor 202.This spent shale can be injected directly into the combustor 202, or inan alternative, a set of six vane rotary lock hopper valves 204 cancontrol flow of spent shale into a rotary distributor 206. The combustor202 can operate to combust any residual kerogen, hydrocarbons or othermaterials in order to produce a flue gas. As non-limiting examples, thecombustor can be a fluid bed combustor or a down flow bed combustor. Forexample, a grate or other spent shale removal device 210 can be orientedin a bottom portion of the combustor and adapted to direct and movecombusted spent shale toward a shale outlet 212. Combusted shale canthen be disposed of and typically has a temperature less than about 400°F.

An air supply (e.g. or other oxygen supply source) can be directed intoan air inlet at a bottom oxidizer inlet 214 via a suitable pump 216. Anair distributor 218 can introduce the air supply into the combustorwhere combustion takes place to burn residual materials and produce theflue gas containing a recoverable heat value. The combustor flue gas canbe removed from the combustor 202 via an upper combustor outlet 208 anddirected to a heat exchanger 220. This heat exchanger 220 can be used topreheat incoming working fluid (e.g. often about 250° F.) to a preheatedworking fluid temperature of about 850-900° F. This working fluid canthen be introduced into retort 106.

Cooled flue gas can then be directed to a scrubber 222 via pump 224where SO2 can be removed. An optional ESP (electrostatic precipitator)226 can further reduce particulates and dust prior to atmosphericventing via an exhaust stack 228.

Working gas and product removed from the radial flow retort 100 can besent to a condenser or distillation column 230 via an optional ammoniuminjector and venturi scrubber 232. Column 230 can be used to condenseand recover liquid hydrocarbon products via pump 234 to separator 236.Liquids removed from the column can be separated into ammoniated waterand oil to storage. Final product oil can be sent to storage whileammonia can be reconditioned or recycled via pump 238 and cooler 240.Ammonia make up may be added to the working gas/hydrocarbon productstream and the stream may be sent to column 230. Ammonia make up andwater make up (via water line 242) can also be fed into the column 230.Gas from the separator can be stored or recycled for use as the workinggas in the retort. Non-condensed working fluid can then be recycled backto heat exchanger 220 via pump 244 or sent as net gas to treating andrecovery. This working gas from column 230 typically has a temperatureof only about 150 to 180° F., depending on particular operatingconditions.

Optionally, a portion of flue gas from combustor 202 can be directed toa steam production unit 246 prior to introduction into scrubber 222 viapump 248. In this manner, steam can be produced from a water source. Insome cases the flue gas can have a relatively high temperature of about2400° F. such that produced steam may be used for driving a steamturbine (not shown) or for other uses.

FIG. 3 shows another example radial retort 300 which includes catalyticheaters 302 within the central heating fluid conduit 118. Othercomponents can be generally as described in connection with radialretort 100 above. Notice in this case, however, that working fluid canbe introduced into the radial retort 300 via a lower inlet 304. Insteadof flowing heating fluid in an inward direction as in FIG. 1, in thisexample the heating fluid flows in a radially outward direction throughthe annular body 114. Heating fluid is fed into the bottom of the retortinto the center pipe. The heating fluid can include one or more ofsteam, fuel and oxygen in order to facilitate catalytic reaction andconversion of hydrocarbons within the central conduit 118. This alsoallows the catalytic heaters to heat the heating fluid before theheating fluid flows outwardly through the annular oil shale bed. Thecatalytic heaters can heat the heating fluid with or without steamassistance. Use of the catalytic heaters in the retort can further allowthe retort to function without recycling a working fluid, other than therecycle of water for steam if steam assistance is used. Furthermore,effluent can be removed from radial retort 300 via an upper exhaust 306and can include hydrocarbons, carbon dioxide, water, hydrogen, etc. Thecatalytic heaters can include a catalyst suitable for catalyzing areaction between the fuel and the oxygen to generate heat.

FIG. 4 shows a processing system 400 similar to FIG. 2 with a radialretort and additional equipment. In this example, the radial retort 300includes catalytic heaters in the center pipe as described above inconnection with FIG. 3. Fuel 402, oxygen 404, and steam 406 can be fedinto the center pipe as the heating fluid. The catalytic heaters heatthe heating fluid and the heating fluid flows in an outward directionthrough the bed of oil shale. In this example, the steam for the heatingfluid can be provided by a heat exchanger 408 that is heated using theflue gas (2400° F.) from the combustor 202. Oxygen 406 can be obtainedcommercially or can be extracted from ambient air 410 via compressors412 and 414 and optional pressure swing adsorption (PSA) generator orother oxygen concentrator 416.

The effluent from the radial retort 300 can be fed through a venturiscrubber 418 to a separator column 420 similar to the sub-systemdescribed above. Product hydrocarbon gas can be withdrawn from the topof the separator column 420 for treating and recovery. Liquid from thebottom of the separator can be further separated into ammoniated waterand oil for storage. Other equipment in this example is similar to theexample in FIG. 2. For example, exhaust flue gas from combustor 202 canbe sent to a scrubber 422 and optional electrostatic precipitator 424prior to exhaust via stack 426.

In one alternative example, the retort vessel can include one or morezones. For example, multiple zones can be created by providing divisionsalong the axial dimension of the outer heating fluid annulus 116. As ageneral guideline, the outer annulus can be divided into one or moresections where fluids of differing temperatures and/or compositions canbe fed and simultaneously flow into the center pipe. For instance, a 60ft long basket could be divided into two sections where the top section,e.g. 40 ft long, passes a hot fluid, e.g. 900° F., from the outer basketthrough downflowing shale and into the center pipe. An additional amountof fluid, e.g. cooler than that input to the top 40 ft section, can flowinto the lower, e.g. 20 ft, annular area created by the lower 20 ft ofouter basket. This cooler fluid also flows radially, contacting thedownward flowing shale, ostensibly cooling the shale, and passing intothe center pipe. In the center pipe this fluid combines with the fluidflowing from the topmost section and exits the retort as a commingledstream. Optionally, there may be small baffles to retard the flow offluids between zones. Regardless, the zones are mostly created by theinjection of the working fluid at different levels. Therefore, there canbe a physical structure in the center or outer basket (e.g. FIG. 1versus FIG. 3) where the working fluid is injected (e.g. not the sideacting as the collector). For instance, if the fluid was injected in theouter shell and flows into the center pipe the physical structure tosegregate would be in the outside basket such that it would be locatedradial, from the vessel wall and attached to the basket.

In one example, the retorting/removal of hydrocarbons and cooling of thespent shale is accomplished in a single vessel. In this example, it maynot be desirable to combust the cooled, spent shale. The same operationcan also be accomplished in separate vessels, namely one for retortingand one for cooling in a manner similar to that accomplished where theretorting and combustion of spent shale is accomplished in separatevessels.

FIG. 5 illustrates a portion of an inward radial flow retort similar toFIG. 1 that allows for varied temperature zone and treatment of solids,depending on their retort phase. For example, an upper zone 502 canprovide heating fluid from a common volume within the outer heatingfluid annulus 116. Heating fluid can be segregated from a middle zone504 via a zone baffle 506. Heating fluid in the upper zone 502 can flowinto the annular body 114 of oil sale at relatively lower temperaturefor preheating and drying. Depending on process conditions, this canresult in less attrition/fines generation due to control of evaporationrates. Notably, fines are generally not good for radial flow systems andcan restrict the inside flow across screens (130,132) which may lead toa shutdown, channeling, or interruption of processing. The middle zone504 of flow can be maintained at retort temperatures for the bulk ofexposure down the reactor. The middle zone 504 can be separated from alower zone 508 by zone baffle 510. The lower zone 508 shown can befinishing zone operating at relatively higher temperature to ensure nooils are remaining on the spent shale or could be circulated withrecirculated retort gas on the way to heating loops as a heat recoverystage, before the shale exits the retort, improving energy recovery ofthe system. In one alternative, a common plenum oriented outside of thezones and within the vessel body can feed each of the zones.Alternatively, multiple dedicated heating fluid inlets can directheating fluid into the vessel at each zone.

In one optional aspect, recirculation of gas to different outer basketzones can be configured in parallel. One advantage of the radial flowapproach is maintaining a similar pressure drop thru the bed in eachzone, which can minimize leakage between the zones, so one can processshale at different conditions within the moving bed. The retort gasreheat temperature and flows to the different zones can be controlled bysuitable piping, heating control, and splitting systems external to theretort. For example, in one alternative, a plurality of working fluidinlets can be oriented on a side of the retort body 106. In this manner,working fluid of different temperatures can be directed to each of theplurality of zones.

FIG. 6 is a flowchart of an example method 700 of extractinghydrocarbons from oil shale. The method includes loading 710 comminutedoil shale into a radial flow oil shale retort, wherein the radial flowoil shale retort comprises a central heating fluid conduit having apermeable outer wall. An outer heating fluid annulus can be positionedabout the central heating fluid conduit, while the outer heating fluidannulus can have a permeable inner wall. Furthermore, the comminuted oilshale can be loaded into a space between the permeable outer wall of thecentral heating fluid conduit and the permeable inner wall of the outerheating fluid annulus. The method can also include flowing 720 a heatingfluid in a radial direction between the central heating fluid conduitand the outer heating fluid annulus to heat the comminuted oil shale andextract hydrocarbons therefrom. The method can also include collecting730 the extracted hydrocarbons.

The described features, structures, or characteristics may be combinedin any suitable manner in one or more examples. In the precedingdescription numerous specific details were provided, such as examples ofvarious configurations to provide a thorough understanding of examplesof the described technology. One skilled in the relevant art willrecognize, however, that the technology may be practiced without one ormore of the specific details, or with other methods, components,devices, etc. In other instances, well-known structures or operationsare not shown or described in detail to avoid obscuring aspects of thetechnology.

The foregoing detailed description describes the invention withreference to specific exemplary embodiments. However, it will beappreciated that various modifications and changes can be made withoutdeparting from the scope of the present invention as set forth in theappended claims. The detailed description and accompanying drawings areto be regarded as merely illustrative, rather than as restrictive, andall such modifications or changes, if any, are intended to fall withinthe scope of the present invention as described and set forth herein.

What is claimed is:
 1. A radial flow oil shale retort, comprising: acentral heating fluid conduit having a permeable outer wall; an outerheating fluid annulus positioned about the central heating fluidconduit, the outer heating fluid annulus having a permeable inner wall;an annular body of comminuted oil shale between the permeable outer wallof the central heating fluid conduit and the permeable inner wall of theouter heating fluid annulus; and a heating fluid supply connected toeither the central heating fluid conduit or the outer heating fluidannulus to flow a heating fluid in a radial direction through theannular body of comminuted oil shale.
 2. The radial flow oil shaleretort of claim 1, wherein the heating fluid supply is connected to thecentral heating fluid conduit to flow the heating fluid in a directionfrom the central heating fluid conduit to the outer heating fluidannulus.
 3. The radial flow oil shale retort of claim 1, wherein theheating fluid supply is connected to the outer heating fluid annulus toflow the heating fluid in a direction from the outer heating fluidannulus to the central heating fluid conduit.
 4. The radial flow oilshale retort of claim 1, further comprising a catalytic heater in thecentral heating fluid conduit or in the outer heating fluid annulus,wherein the catalytic heater produces heat by a chemical reaction ofhydrocarbons in the heating fluid.
 5. The radial flow oil shale retortof claim 1, further comprising a rotary shale distributor positionedabove the annular body of comminuted oil shale to distribute oil shalebetween the permeable outer wall of the central heating fluid conduitand the permeable inner wall of the outer heating fluid annulus.
 6. Theradial flow oil shale retort of claim 1, wherein the heating fluidcomprises steam.
 7. The radial flow oil shale retort of claim 1, whereinthe heating fluid comprises hydrocarbons.
 8. The radial flow oil shaleretort of claim 1, wherein the heating fluid comprises oxygen.
 9. Theradial flow oil shale retort of claim 1, further comprising a combustorunit and a shale withdrawal conduit to convey spent shale to thecombustor, wherein the combustor generates heat by combusting the spentshale.
 10. The radial flow oil shale retort of claim 9, wherein thecombustor is a fluid bed combustor or a down flow bed combustor.
 11. Theradial flow oil shale retort of claim 1, further comprising a vapor/gasproduct outlet connected to either the central heating fluid conduit orthe outer heating fluid annulus, whichever is not connected to theheating fluid supply.
 12. The radial flow oil shale retort of claim 1,further comprising a liquid product outlet in fluid communication withthe annular body of comminuted oil shale to collect liquid hydrocarbonproducts produced from the comminuted oil shale.
 13. The radial flow oilshale retort of claim 1, further comprising a heating unit connected tothe heating fluid supply to heat the heating fluid before the heatingfluid flows through the annular body of comminuted oil shale.
 14. Theradial flow oil shale retort of claim 1, wherein the dimensions of theretort include the diameter at the outer walls of the retort from 10feet to 100 feet or about 40 feet; the diameter at the permeable innerwall of the outer heating fluid annulus from 9 feet to 90 feet or about38 feet; the diameter at the permeable outer walls of the centralheating fluid conduit from 1 foot to 10 feet or about 6 feet; a beddepth measured from the permeable outer wall of the central heatingfluid conduit to the permeable inner wall of the outer heating fluidannulus from 1 foot to 80 feet or about 16 feet; a bed height measuredin the axial direction of the retort from 10 feet to 300 feet.
 15. Amethod of extracting hydrocarbons from oil shale, comprising: loadingcomminuted oil shale into a radial flow oil shale retort, wherein theradial flow oil shale retort comprises: a central heating fluid conduithaving a permeable outer wall, and an outer heating fluid annuluspositioned about the central heating fluid conduit, the outer heatingfluid annulus having a permeable inner wall, wherein the comminuted oilshale is loaded into a space between the permeable outer wall of thecentral heating fluid conduit and the permeable inner wall of the outerheating fluid annulus; flowing a heating fluid in a radial directionbetween the central heating fluid conduit and the outer heating fluidannulus to heat the comminuted oil shale and extract hydrocarbonstherefrom; and collecting the extracted hydrocarbons.
 16. The method ofclaim 15, wherein the comminuted oil shale is substantially stationaryduring the extraction of the hydrocarbons, and further comprisingloading and unloading the comminuted oil shale from the retort, suchthat the process is a batch process.
 17. The method of claim 15, whereinthe comminuted oil shale continuously flows through the retort such thatthe process is continuous.
 18. The method of claim 17, furthercomprising continuously loading comminuted oil shale into the retort andcontinuously withdrawing spent oil shale from the retort.
 19. The methodof claim 17, wherein the comminuted oil shale flows downward at a speedof 1 inch per hour to 100 feet per hour.